基于Copula相依函数的安徽省气温与降雨量相关性研究

发布时间：2018-05-01 17:35

本文选题：气温 + 降雨量　；参考：《长江流域资源与环境》2017年01期

【摘要】：当前全球气候变暖大背景下,气温和降雨量的交互作用引致农业气象灾害频发,给农业生产造成破坏性风险损失,因此探讨气温与降雨量之间的动态相依关系尤为重要。搜集安徽省24个气象观测站1980~2014年的气温与降雨量日数据,对原始数据进行矩平均处理,使两组数据列满足独立同分布的要求。采用非参数核估计的方法确定气温与降雨量的边缘分布。根据降雨量和气温的均匀分布散点图和频数分布直方图可知,安徽省气温和降雨量之间呈现一定程度的负相依关系,即图形中表现出气温与降雨量的上下尾之间的对称性。综上分析,选择可以刻画两个变量具有上下尾对称关系的Copula函数对气温与降雨量的相依关系进行拟合,最终在平方欧式距离最小的原则下选定二元t-Copula函数做出气温与降雨量之间的联合概率密度函数图。研究结果发现:1据安徽省气温与降雨量联合概率分布可知,当降雨量上升时,气温下降;或气温上升时,降雨量会下降,气温与降雨量之间呈现为中等负相关关系( 0.280)。2极值相关性方面,从t-Copula密度函数图和上下尾相关系数看,安徽省气温与降雨量在极值方面具有较为明显的相依关系,表现为当气温和降雨量超过正常范畴时,二者相依关系从负相关转变为正相关,此现象多出现在极端气候条件下,例如极端高温和大暴雨时气温与降雨量的正相依性。
[Abstract]:Under the background of global warming, the interaction of temperature and rainfall leads to frequent agrometeorological disasters, which results in destructive risk loss of agricultural production. Therefore, it is important to explore the dynamic dependence between temperature and rainfall. The daily temperature and rainfall data of 24 meteorological observation stations in Anhui Province from 1980 to 2014 were collected, and the raw data were processed by moment average, so that the two sets of data columns could meet the requirements of independent and same distribution. The nonparametric kernel estimation method is used to determine the marginal distribution of temperature and rainfall. According to the uniform distribution of precipitation and temperature and the histogram of frequency distribution, it can be seen that there is a negative correlation between temperature and rainfall in Anhui Province, that is, the symmetry between temperature and rainfall is shown in the graph. On the basis of the above analysis, the Copula function, which can describe the symmetries between the two variables, is selected to fit the dependent relationship between air temperature and rainfall. Finally, under the principle of least square Euclidean distance, the binary t-Copula function is selected to make the joint probability density function diagram between temperature and rainfall. The results show that according to the combined probability distribution of temperature and rainfall in Anhui Province, when the rainfall rises, the temperature decreases; or when the temperature rises, the rainfall drops. There is a moderate negative correlation between air temperature and rainfall (0.280n.2 extreme value correlation). From the t-Copula density function diagram and the correlation coefficient between upper and lower tail, the temperature and rainfall in Anhui Province have obvious dependence on extreme value. When the temperature and rainfall exceed the normal category, the dependence of temperature and rainfall changes from negative to positive. This phenomenon often occurs in extreme climatic conditions, such as extreme high temperature and heavy rain, the positive dependence of temperature and rainfall.
【作者单位】：华东师范大学统计学院;华东师范大学地理信息科学教育部重点实验室;
【基金】：国家自然科学基金(71403088) 国家社科基金重大项目(13&ZD161) 高等学校学科创新引智计划(B14019)~~
【分类号】：S161

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